The world's longest running survey on human health and happiness is being digitized to benefit the next generation of researchers. The database will unite the results of two studies that began tracking individuals in their teens, accounting for both controllable and uncontrollable factors that affect healthy aging. "Over the years, researchers have studied the effects of World War II combat, substance abuse, childhood trauma, education, and other factors." Today, surviving subjects are in their 80s or 90s.

What's the Big Idea?

Though researchers have been gathering and analyzing data for 40 years, they say the project still stores surprises. Just last year, it was discovered that 57 percent of divorces in the study were related to alcohol abuse (individuals had not been comfortable discussing their partner's drinking problem until later in life). Overall, researchers conclude that decisions made in middle-age are more important determiners of longevity and late-life happiness than the conditions under which one was born.